The present invention relates generally to speech recognition, and more specifically to an enrollment method for generating speech recognition templates.
One difficulty encountered in the machine recognition of connected speech is the fact that words spoken in a connected utterance can differ significantly from the same words spoken in isolation. These differences occur for several reasons. One reason is that the words spoken in connected speech are typically shorter than the same words spoken in isolation. The second difference is due to coarticulation effects of words spoken in connected speech.
Another problem encountered in speech recognition systems generally is the difficulty of determining the quality of vocabulary templates during the enrollment phase. The quality of the enrollment is critical to the performance of a speech recognizer. Currently, the only method to test the quality of the enrollment is to actually check the recognition performance of the system using the enrolled templates.
It is therefore an object of the present invention to provide a method for improving the enrollment process for connected word templates. It is another object of the present invention to improve and simplify checking of the quality of the enrollment.
Therefore, according to the present invention, isolated word templates are created of the words in the desired vocabulary. These templates are time compressed, and then used to extract connected word templates from connected speech samples. The extracted connected word templates are used as the vocabulary templates for the connected speech recognizer. The extracted templates can be used to synthesize speech at both the isolated word and connected word levels in order to ascertain the quality of the enrollment.
The novel features which characterize the present invention are defined by the claims. The foregoing and other objects and advantages of the present invention will hereafter appear, and for purposes of illustration, but not of limitation, a preferred embodiment is shown in the accompanying drawings.